Surgical simulacra and process of preparing same



July 20, 1943.

K. HOFFMANN ET AL SURGICAL SIMULACRA AND PROCESS OF PREPARING SAME FiledNov. 50, 1938 Edyar, Flieyen chmia z K ar2 5140mm INVENTORS ATTORNEY 1impa ts of d e terial.

' tract.

crum is mounted, may offer a support corresponding to that given bybones, asit would, for instance,.be the case in connection with a torsoI l shown in Fig.1; The torso is endwisely retained between a rear boardl3 and a front board I2, where a desired yield may be obtained by usingflexible material or even fully elastic and yieldable material likerubber. These two .vbdards are again assembled with each other by way ofa bottom column l0, which substantially offers the reaction of a spine,tubes and portions of the torso, such as the The simulated blood vesseland intestinal tracts, may be connected by tubes or pipes I5 to one ormore'containers M, the supply of fluids being controlled by valves IS.The containers I6 are mounted at a suitablelocation, e. g. upon the rearboard I3,

I so as to furnish heads for the fluids supplied qthereby correspondingto pressure conditions in the ducts or vessels of a humanbody.

In 'a'lateral gridiron incision, the student has first to cutthes'liinlill, has divided the aponeurosis l8.rof the external obliquemuscle along the courseof its fibres; has; separated the latter 7 7 fromthe internal. obliquahas 'separated the lat- 'ter by sharptdissec'tionfrom the1 muscle substance of the internal oblique l9,"has split thelatter and the transversalis muscle and fascia in the directionof theirfibres and, after removal of thepreperitoneal fat, the wound'beingheld-open by retractors 2l,"the cecu1n'22 and.

the appendix 23 are "exposed. Let us start the description of theconstruction of such asimula- With' theintestine's, whichthus have beencrum is made as follows: 1st: Negative mold .or

exposed. Generally speaking, a surgical simula- 2nd: The partsarereproduced; from the, im-V prints, e g. by way of more permanentrmolds,or layers oi the. parts are shaped in suitable ma- 3rd: The reproducedparts assembled.

The (negative) mold may preferably be made by 1irst casting the partscrime cadaver in a temporary (negative) mold, preparing a .temporary(positive) cast of such part in such temporary 'mold, and; thenpreparinga permanent (negative). mold from" such temporary fipositive) at. c s

"be -as: follows in connection with an; intestinal The tract-is.suitably filled to, assume a normal position, e.-. g. ifor 'thelinstantit may be By way of ,example, the procedure may inflated-.- The surfaceis. suitably coated in order to prevent sticking of the 'mold if" thetern} po rary -mold is to be cast according to this'invention in latex,the outer surface of the tract is coveredwitha coagulant, e. g.-a'calcium chloride acetic acid solution. A latex l'ayerlwas' found to setin 3 minutes in a solution containing by weight 1 part of acetic acid,15 .parts of calcium chloride, parts of water.

f Latex is then applied, -e. gl by dipping or preferably it is sprayedon by anordinary spray 'gun. In orderto prevent clogging of thefgun,

the latex sh ould be. fresh. A highjqlatex concentration is desirableand ammonia solution representing about one eighth part or, the

total volume may be added for spraying. After the application of'seyerallayersbf latex, co-

imprin'ts are made of 2,324,702 Z v V a I "with Fig. 3. ,The rubbertubes '24 may. b e! tained in an extended, straight position by smoothsticks 26 removably inserted thereth'rough. Additional layers of latexare now applied and coagulated, embedding ,theicentral portionsfof therubber tubes 24, the endsof said tubes remaining free. The temporarymold 25;

is. now completed. It may be removed from the 'cadaverby pullingthesticks 26 out of the rubber i tubes 24, and'by parting the molds by aclean a cut across the wall containing the rubber tubes 24, whereuponthe temporary mold 25 may. be-

'removed from the organ upon whichit has been formed,.i. e. theappendix, and has the appear- I ance of Fig. 3. 7 After the parting inthe'mois't or remoistenedilatex mold; which therefore is not, shrunk.

From the temporary (positiye) "castj of the appendix a permanent moldmay be obtained,-

i. e. cast'in gypsum, 'or"in stonewhich takes longer for thesetting'than the gypsum. "If the gypsum' mol'd has 'a substantialcentral parting" the partsiof the halves 'of'tl1e'-'twopartite'mold maybe extended'alongsideiof each other GWe; T may suitably coat the cavity,.e. 'g with 'glyoerinef: in orderto prevent a stickingotthe' fihal cast1 a or molding; which is 'tofbe molded separately in-each half ofthemold.

- While latex has not been used heretofore for taking molds from organictissues and anatomic: brgans, 'the'res ults are excellent when th'e'fore-f going procedure is followedgas modified for' cer-l tain purposeshereinafter; Latex yields line and tifue'details; is welladap'tedfor-undercuts, "may 1" readily'befdetached from the tissues;- does Snotpress the specimen out'o'f-shape; can'be caused .7 to set quick-1y,and-yields castsof'tr'ue-size'when kept in a moiststate.This-unexpeeted-new:use ofl'atex does however not fully extend ii e. notin respect to "several parts,'to'the finalpr permai nent cast of thesimulacra." l lowever 'for-gthisv latter purpose, another material'has--been-=con- -verted,"whichheretofore has not been foundadaptable-for positive casts. 'j'IThisis a synthetiq;

rubber-like material, which by itself orjin solur tion' is commonly'knowrras-fmolding of matrix -jel1's, and-which is" adapted 'forrepeatedffusion underheat. Such a material may beidentified I i' for theinstant purposesas an elastic, softand yieldable but form-retaining,-:thermofusible plastic. Consistencyct-the yarious, Il'lOdlfiCfl? tionsoffered themarket: (e. g. Korogel): :may

approach --ormay 1 be controlled to approach the I physicarpropertie'saand: consistency of. all :kinds I of organic tissue;skin'etc whilebone ,:ca rtilage etc. may be readilysimulated in otherfashion;

agulant being alternately 'applied;"a "number of rubber tubes 2 may 'bedeposited substantially across. theeontemplatedj parting plane of the ttemporary mold '25, 'asindijcate'd 'in clonne'ction parallel toife'achotherfupo'n the' latex"layers,

According-to this-iinventionit. may-Jbe preparedin thicknessescorresponding to .thel skins; .also;. in --tensile andcompressivestrength, ':hardness ,g

resiliency, etc. a

- While the molding 'jells 'are BXtIGIIIBIYSUSCGPU ble tofforeignmatter,losing for-instance-their 4 softness and elasticity-and otherpropertieswhefi ffl contaminated," we have found itwell possible-Ito i.i tint these-jells-for purposes of simulation if tl'i'e 'variousorganictissues, when asuitabl c Vtive carrier-is used 'as a base" forthepigmen such atcarrier is planes 28 have been returned into abutment witheachotherand the sticlgsl 26 have been reinserted and extendfullythrough I 1' i Q therubber-tubes 24, thecavity 21 'of the tem- Vporary: mold'25 has resumed its true shape. Fromthis' reassembledtemporary mold; the posi tive cast is made, e. grin paraffinpreferablycast iincexide! nismeainipmsaf fre-moved laiqed; A

' of th be reprodu toens latgd. w

are

shape-d in latex is sprayed on.

cessive layers of latex ontosaid...specimen,- and applying a coagulantto said-specimen before the first one of said layers isjsp'rayedthereunto and to layer. before asliccessiivstep of spraying.

ZjThe method otipreparing an imprint from ansanatomical specimen,comprising successivelyspraying successive layers of latex onto saidspecimen, and applying an acetic acid solution oficalcium chloride tosaid speeimenand to a successively applied layer just before a layer of5 ed to Ebe 'la'stingly shaped under heat and shaped} 1O 8. The methodofpreparirig a moldv froin an anatomical specimen, comprising"coagulating successively applied latexlayers cnsaid specimen, spacecllydepositing rubber tubes on said 7 layers through 1 which smoothstraightening stic'kslar .r'emovably extended, engagingsaid tubes uponsaid layers -by additionally applied 1 and coagulated latex layers;Withdrawing. the

sticks from the tubes, parting the wall of the latex mold thus producedby cutting it' across the buried portions ofthe tubes, removing the tspecimen, 'azid-reinsertingthesticks for realign- 7 ingithe mold in-itstrue outline. 1 7 I '9. A surgical simulacrum'comprising a reproductionof an anatomical duct in a synthetic jell'having .physical properties ofreaction to touch, incision and suture similar to those of the fitiesbut responding to suture and ligationilike such tissue andduct{;r.espective1y.,iand being tacked. together toiyi'eldla relativeorganization 253243702 I V y duct reproduced :in a live'body, and aliquid container connected to said reproduction and serving to placesaid reproduction under a liq uid head cerresponding'to. pressuresnormally prevailing in the reproducedrduct in-the'live body; V

' t0. Asur'gical simulacrum coinprising elements made" :cf; a synthetic,rubberelikeiplasticf adapt in the organization of the anatomicalcorzans;said iplastic being conditioned-t0 corresporidin thelcase of each organsimulated therein to the I live organ in respect to reaction'tofltouch,ine

cisi'on sand suture; said. velements being Y tinted,

fuseriiyinterconnected and assembled in 'sin'ni Station of anatomicalstructmezcfithe simulated organs-.- i

.11. Ina surgical simulacrum' a layerliand a vesselarrangedcorrespondingwe tissue-ands; i, v duct or: a live body; said layer 'andivesselibeing' made of synthetic materials-shaving;lasting :qual

corresponding to the arrangementio-f said tissue and cut in a livebody.I r -.KARL F. .HOFEMANN, V

EDGAR FLIEGENSCHMIDT;

